1. Field of the Invention
This invention relates generally to trocars for use in endoscopic surgery and, more particularly, to a locking device for easy insertion into and removal from an existing opening in a trocar, and for securing an instrument inserted through the trocar into a body cavity in position so as to prevent movement thereof.
2. Description of Related Art
As is well known, surgical devices, such as trocars are widely used in endoscopic surgery. Trocars are devices that are used to provide access to a surgical site within a patient's body cavities. A trocar is typically inserted through a small skin incision by pressing the distal end of the trocar against the outer skin of the patient with sufficient force applied to the trocar handle so that the piercing tip of an obturator effectively penetrates the patient's skin and underlying fat tissue, fascia, muscle and into a selected internal cavity. The trocar obturator is removed and the trocar cannula is then used as a passageway to and from the patient's body cavity. During many procedures a number of trocars are required so that a number of passageways are formed into the selected body cavity, to enable a surgeon to concurrently use an endoscope and one or more other devices inserted into the body cavity.
An example of a known trocar is shown in U.S. Pat. No. 5,256,149 to Banik et al. This patent discloses a trocar constructed from a transparent plastic material and includes a trocar cannula with a cannula handle, a cannula tube and a trocar obturator passing through the handle and tube. The device also includes a gas inlet having a valve thereon to enable a gas to be used to insufflate and desufflate a body cavity into which the trocar cannula has been inserted and is held. After the obturator is used to pierce a person's body and form an opening into an underlying body cavity, the trocar cannula may be threaded into the opening formed into the body cavity with a stability thread to aid in securing the trocar cannula in place. The obturator is removed from the trocar cannula, and an instrument such as an endoscope, an endoscopic needle grasper, a holding device, a manipulating device, or the like, may be inserted through the trocar cannula into the body cavity.
During many types of surgery a number of trocars are inserted so that there are a number of passageways into the selected body cavity. One or more of these passageways may be used to move or position an organ if a further portion thereof must be seen or operated on. In addition, the organ may cover or block another organ which needs to be examined or operated on. This is usually accomplished by the insertion of a grasping or manipulating device or instrument, into a passageway in one of the trocars. However, the grasping or manipulating instrument is usually loosely aligned in the trocar passageway and must be held in position or somehow secured so that any organ or the like that it is pressing against or supporting, does not move or shift. Since the surgeon and/or assistant must concentrate on specific steps and requirements during a surgical procedure, and often need both of their respective hands, a holding means or another person must help to hold or support the grasping or manipulating device. Often, however, it is left to the surgeon or assistant to try to hold the instrument steady by the use of a surgical clamp between the instrument and a surgical drape on the patient, or somehow jury rig a means to hold or support the instrument. For numerous reasons, surgeons and their assistants have difficulty in fully or properly holding or supporting such instruments, and problems have occurred. Therefore, a need exists for a simple and effective means for holding a grasping or manipulating instrument in place in a trocar during surgical procedures, such as endoscopic surgery.